Power transmission casing apparatus in motorized two-wheeled vehicle

ABSTRACT

A power transmission casing apparatus in a motorized two-wheeled vehicle which comprises a case main body extending from one lateral side of an internal combustion engine to one lateral side of a rear wheel in rear thereof and supporting rotatably a wheel axle of the rear wheel. The case main body is applied with a cover member for containing therein liquid-tightly a reduction gear means, and is applied with another cover member for containing therein a V-belt means.

BACKGROUND OF THE INVENTION

This invention relates to a power transmission casing apparatus in amotorized two-wheeled vehicle such as a motorcycle or the like.

In general, it is preferable in a two-wheeled vehicle of this kind touse a V-belt means with the intention of transmitting an output of aninternal combustion engine to a rear wheel provided in rear thereof,because there is a comparatively large distance between an output shaftof the engine and a wheel axle of the rear wheel. And it is required forthis case to provide a reduction gear means for reducing a speed of theoutput shaft because it is comparatively high in rotation speed, andadditionally it is preferable in this case that the reduction gear meansbe located on the rear wheel side, that is, inside the V-belt means andalso be of such a wet type as immersed in oil.

SUMMARY OF THE INVENTION

This invention has for its object to provide an apparatus in which theV-belt means and the wet type reduction gear means with the location asabove are contained in a single common casing and the whole of theapparatus is small-sized. The invention is characterized in that a casemain body extending from one lateral side of an internal combustionengine to one lateral side of a rear wheel in rear of the engine andsupporting pivotally an axle of the rear wheel is applied at itsrearward portion with a transmission cover member which covers areduction gear means comprising the wheel axle, an input shaft and agear train connecting therebetween in a fluid tight manner, and isapplied at its front portion with a V-belt cover member which covers aV-belt means comprising a pulley on the input shaft passing through thetransmission cover member, a pulley on an output shaft of the engine anda V-belt connecting between the two pulleys.

DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the accompanyingdrawings, in which

FIG. 1 is a side view of one example of this invention apparatus appliedto a motorized two-wheeled vehicle,

FIG. 2 is an enlarged sectional plan view of the same, and

FIG. 3 is a side view, partly omitted, thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT

One embodying example of this invention will be explained with referenceto the accompanying drawings:

Referring to the drawings, numeral 1 denotes a vehicle body for amotorcycle or the like, numeral 2 denotes a front wheel thereof, numeral3 denotes a rear wheel of the same, and numeral 4 denotes an internalcombustion engine interposed between the two wheels. There is provided acase main body 6 which extends from one lateral side of the engine 4 toone lateral side of the rear wheel 3 so as to form a rearwardlyextending rigid frame. The main body 6 rotatably supports a wheel axle 5of the rear wheel 3. The case main body 6 is partitioned at its interiorinto a front casing section 6a and a rear casing section 6b. The rearcasing section 6b is applied with a transmission cover member 10 in afluid tight manner so as to form a transmission chamber B, and the frontcasing section 6a is applied with a V-belt cover member 16 so as to forma V-belt chamber A.

The chamber B contains therein a reduction gear means 9 comprising thewheel axle 5, an input shaft 7 on the forward side of the wheel axle 5and a gear train 8 interconnecting therebetween, and is charged withoil.

The chamber A contains therein a V-belt means comprising a pulley 11mounted on a protruded portion of the input shaft 7 passing through thecover member 10, a pulley 13 mounted on an output shaft 12 of the engine4 located in front of the input shaft 7 and a V-belt 14 extending andconnecting between the two pulleys 11, 13. Thus, the case main body 6 isformed together with the cover members 10, 16 into an integrallycombined assembly which contains in its rear section the reduction gearmeans 9 of wet type and in its front section the V-belt means 15 of drytype, in such an arrangement that the former 9 is closed to the rearwheel 3 and the latter 15 is located outside the same. An automaticcentrifugal clutch means 17 is provided on an outer end of the inputshaft 7. The case main body 6 is formed integrally, at its front endportion, with the side surface of the casing of the engine so as toconstitute as a whole a power unit, and this unit is swingably attachedto the vehicle body 1 side through a pivot 18 provided at its frontupper end portion.

The transmission cover member 10 has a portion extending rearwardsbeyond the rear end of the V-belt cover member 16, and is provided atthat extended portion with an oil charging opening 19 and an oildischarging opening 20 for interchanging of interior lubrication oilwith a new one, and thus the work of interchanging of the oils can becarried out without detaching the V-belt cover member 16. In respect ofthe V-belt 14, it can be interchanged simply by detaching the covermember 16 alone. The case main body 6 is so formed that its plane onwhich the cover member 10 is to be put and its plane on which the covermember 16 is to be put are in the same plane, so that the same can beworked, for instance, by a milling cutter and the workability thereofcan be improved. The case main body 6 and the V-belt cover member 16 areformed into such a convenient combination one that the two are put oneupon another directly without using an interposed packing or the liketherebetween and are joined together by screws such as bolts or thelike, and thereby the cover member 16 can serve as an reinforcing memberso as to increase the rigidity of the case main body 6.

Numeral 21 denotes a kick shaft for starting the engine 4, and numeral22 denotes a starter gear train extending therefrom.

MODE OF OPERATION

The operation of the apparatus will be explained as follows:

The output of the engine 4 is transmitted through the V-belt means 15and the reduction gear means 9 to the rear wheel 3, so that the vehicleis driven to run. In this apparatus, the two means 15, 9 are containedin the single common covered case main body 6 in front and rearrelationship, so that the whole thereof becomes comparatively small insize. Additionally, the reduction gear means 9 is applied with thetransmission cover member 10 in a fluid tight manner and the lubricationoil is held therein and thus the same can be always secured in a goodlubrication condition.

Thus, according to this invention, the case main body extending in thefront and rear directions is applied with the cover members and containstherein the reduction gear means and the V-belt means in front and rearrelationship, so that the whole of the casing apparatus can be obtainedwith a comparatively small-sized one, and the reduction gear means isapplied on its outer surface with the cover member liquid-tightly, sothat lubrication oil can be held therein and the reduction gear meanscan be always kept in a good lubrication condition.

What we claim is:
 1. A power transmission casing apparatus in amotorized two-wheeled vehicle comprisinga case main body extending fromone lateral side of an internal combustion engine to one lateral side ofa rear wheel positioned rearwardly of said engine, said case main bodyrotatably supporting a wheel axle of said rear wheel and partiallyhousing in a rear portion a reduction gear means which comprises thewheel axle, an input shaft, and a gear train operatively interconnectingthe input shaft to the wheel axle, said casing apparatus also housingV-belt means comprising a rear pulley on the input shaft, a forwardpulley on an output shaft of the engine and a V-belt operativelyconnecting the pulleys, each of the pulleys having a circumferentialperiphery; a transmission cover member sealingly engaging with said casemain body in a fluid tight manner and extending to enclose saidreduction gear means, said input shaft extending through saidtransmission cover member; and a V-belt cover sealingly engaging withthe case main body and extending from beyond the forwardmost portion ofthe periphery of the forward pulley to beyond the rearmost portion ofthe periphery of the rear pulley to enclose the V-belt means.
 2. A powertransmission casing apparatus in a motorized, two-wheeled vehicle asclaimed in claim 1, further comprising an engine casing, said enginecasing being integral with said case main body.
 3. A power transmissioncasing apparatus in a motorized two-wheeled vehicle as claimed in claim1, wherein the transmission cover member has a portion extendingrearwards beyond the V-belt cover member and is provided at that portionwith oil charging and discharging openings.